Some questions concerning the Blakers et al. case that pumped hydro storage can enable 100% electricity supply

Blakers et al. claim that pumped hydro storage will enable a 100% renewable electricity supply for Australia. However aspects of their case are questionable and require clarification or confirmation. This study seeks to discuss these, not with the aim of settling questions but of pointing to issues that would require verification before the viability of the proposal could be regarded with confidence. •The significance of the claims by Blakers et al. is noted.•However concerns regarding several aspects of their scenario are raised.•It is argued that these concerns indicate that the account is too optimistic.•Much more work would be needed to establish the viability of PHS.